Search Results (4)

Background/Objectives: Canine intervertebral disc herniation (IVDH) is an important musculoskeletal pathology. Unlike in humans, IVDH mechanisms in dogs are underinvestigated from a system-level integrative omics point of view. The aim of this study was to identify key serum molecular players in canine IVDH. Methods: An integrative multi-omics approach combining high-resolution LC-MS-based untargeted metabolomics and tandem mass tag (TMT)-based proteomics was applied. Additionally, serum zinc concentration was determined by spectrophotometry. Results: Nineteen serum metabolites were differentially abundant in IVDH dogs. Metabolite analysis highlighted dysregulation in lipoic acid and branched-chain amino acid (BCAA) metabolism, with elevated levels of valine, leucine, and isoleucine in IVDH. These findings suggest disrupted energy, nitrogen, and neurotransmitter metabolism, potentially contributing to the IVDH pathophysiology. Additionally, lower serum uridine, possibly influenced by BCAA accumulation, was observed, indicating altered neuroinflammatory responses. ELISA validation confirmed elevated serum levels of zinc-α2-glycoprotein (ZAG), alpha-1-microglobulin/bikunin precursor (AMBP), and vitronectin (VTN) in IVDH, supporting immune modulation and neuroprotective mechanisms. Serum prekallikrein (KLKB1) and Protein C inhibitor (SERPINA5), involved in fibrin cloth formation, were found to be lowered in IVDH patients. Pathway enrichment revealed disturbances in aromatic amino acid biosynthesis, with elevated phenylalanine, tyrosine, and tryptophan influencing neurotransmission and inflammation. In addition, elevated serum Zn concentration emphasized its antioxidant importance in immune response, wound healing, and neuropathic pain signaling. Conclusions: Integration with our prior CSF multi-omics data reinforced the relevance of identified molecules in IVDH-associated neurodegeneration, inflammation, and repair processes. This study offers insight into potential diagnostic biomarkers and therapeutic targets for canine IVDH through serum-based molecular profiling. Full article

Proteoglycans consist of proteins linked to sulfated glycosaminoglycan chains. They constitute a family of macromolecules mainly involved in the architecture of organs and tissues as major components of extracellular matrices. Some proteoglycans also act as signaling molecules involved in inflammatory response as well as cell proliferation, adhesion, and differentiation. Inborn errors of proteoglycan metabolism are a group of orphan diseases with severe and irreversible skeletal abnormalities associated with multiorgan impairments. Identifying the gene variants that cause these pathologies proves to be difficult because of unspecific clinical symptoms, hardly accessible functional laboratory tests, and a lack of convenient blood biomarkers. In this review, we summarize the molecular pathways of proteoglycan biosynthesis, the associated inherited syndromes, and the related biochemical screening techniques, and we focus especially on a circulating proteoglycan called bikunin and on its potential as a new biomarker of these diseases. Full article

Aim: The aim of this study was to assess if the ovine articular cartilage serine proteinase inhibitors (SPIs) were related to the Kunitz inter-α-trypsin inhibitor (ITI) family. Methods: Ovine articular cartilage was finely diced and extracted in 6 M urea and SPIs isolated by sequential anion exchange, HA affinity and Sephadex G100 gel permeation chromatography. Selected samples were also subjected to chymotrypsin and concanavalin-A affinity chromatography. Eluant fractions from these isolation steps were monitored for protein and trypsin inhibitory activity. Inhibitory fractions were assessed by affinity blotting using biotinylated trypsin to detect SPIs and by Western blotting using antibodies to α1-microglobulin, bikunin, TSG-6 and 2-B-6 (+) CS epitope generated by chondroitinase-ABC digestion. Results: 2-B-6 (+) positive 250, 220,120, 58 and 36 kDa SPIs were detected. The 58 kDa SPI contained α1-microglobulin, bikunin and chondroitin-4-sulfate stub epitope consistent with an identity of α1-microglobulin-bikunin (AMBP) precursor and was also isolated by concanavalin-A lectin affinity chromatography indicating it had N-glycosylation. Kunitz protease inhibitor (KPI) species of 36, 26, 12 and 6 kDa were autolytically generated by prolonged storage of the 120 and 58 kDa SPIs; chymotrypsin affinity chromatography generated the 6 kDa SPI. KPI domain 1 and 2 SPIs were separated by concanavalin lectin affinity chromatography, domain 1 displayed affinity for this lectin indicating it had N-glycosylation. KPI 1 and 2 displayed potent inhibitory activity against trypsin, chymotrypsin, kallikrein, leucocyte elastase and cathepsin G. Localisation of versican, lubricin and hyaluronan (HA) in the surface regions of articular cartilage represented probable binding sites for the ITI serine proteinase inhibitors (SPIs) which may preserve articulatory properties and joint function. Discussion/Conclusions: The Kunitz SPI proteins synthesised by articular chondrocytes are members of the ITI superfamily. By analogy with other tissues in which these proteins occur we deduce that the cartilage Kunitz SPIs may be multifunctional proteins. Binding of the cartilage Kunitz SPIs to HA may protect this polymer from depolymerisation by free radical damage and may also protect other components in the cartilage surface from proteolytic degradation preserving joint function. Full article

Diabetic nephropathy (DN) is a major complication in diabetic patients. Microalbuminuria testing is used to identify renal disease; however, its predictive value is questionable. We aimed to identify urinary biomarkers to early diagnosis nephropathy before identifiable alternations in kidney function or urine albumin excretion occurs. Proteomic approaches were used to identify potential urinary biomarkers and enzyme-linked immunosorbent assay was performed to verify the results. The data identified haptoglobin (HPT) and α-1-microglobulin/bikunin precursor (AMBP) as two biomarkers with the highest ability to distinguish between healthy individuals and patients with nephropathy, and between diabetic patients with and without DN. Further, the HPT-to-creatinine ratio (HCR) was evaluated as an independent predictor of early renal functional decline (ERFD) in a cohort with an average follow-up of 4.2 years. The area under the curve (AUC) value for ERFD prediction was significantly improved when the HCR biomarker was included in the model with albumin to creatinine ratio (ACR) and baseline characteristics (AUC values were 0.803 and 0.759 for HCR and ACR, respectively; p value was 0.0423 for difference between models). In conclusion, our results suggest that HCR represents an early indicator of nephropathy, and a marker related to ERFD among diabetic patients in Taiwan. Full article